(1) Field of the Invention
This invention relates to a method for recognizing the leading edge of a character printed in magnetic ink in E13B font.
(2) Background Information
Documents like checks and deposit slips used in the banking industry, for example, have certain key data printed on the documents in magnetic ink in particular fonts, like E13B. The key data includes, bank number, customer account number, document or check number, and the monetary amount of the document, for example. The documents with this key data thereon are processed by banking machines, like proof and sorting machines. The processing is effected by moving the documents with the key or MICR data thereon in reading relationship with a magnetic or MICR reader positioned along a document track included in the banking machines. As a document is moved in the document track past the MICR reader, waveforms are generated by the MICR reader. Each character within a particular font is printed so as to have its own individual waveform generated by the MICR reader. One characteristic of E13B font is that each character within the font always starts with a positive-going waveform to indicate the start of a character. The output signals from the MICR reader are processed for thresholding, for example, and then they are processed by character recognition circuitry to identify the waveforms being read as being indicative of individual characters within that particular font.
There are four general situations which cause problems with the reading of characters which are printed in E13B font. These situations are:
1. Characters which are not printed according to predetermined specifications. These include characters with ragged edges, characters with broken elements, and characters with missing elements. Even though a character is printed correctly, initially, some of the situations mentioned here may develop through abusive handling of the document on which the characters are printed.
2. Characters with extraneous MICR ink spatter nearby. This is commonly referred to as EIF.
3. Characters with pitch problems. Character pitch is most easily defined as the distance between the rightmost edge of one character to the rightmost edge of an adjacent character printed in the same font.
4. Misreads. A "misread" occurs when the character recognized by the recognition circuitry is not the same as the corresponding actual character appearing on the document.
The situations mentioned cause rejects to occur when the documents are being read by a MICR reader. The rejects occur at a typical reject rate of about 2%. When documents are fed or moved past a MICR reader at a rate of 400 to 500 documents per minute, even a reject rate of only 2% generates a large number of documents which have to be reprocessed.